The first three etymologies indicate that the word origin was derived from the latin noun origo f (http://en.wiktionary.org/wiki/origo) which in turn was derived from the verb oriri.

For this to occur one would have to take the stem of the verb oriri and then add the suffix -go to get origo f, although I can’t find a source confirming this to be a possibility which is a worry.

Where did the consonant g come from in the word origo, was g part of a common suffix used to form nouns at the time, or is there something else going on in the formation of the noun origo? On that issue the last part of the fourth etymology can perhaps shed some light “- L. originatio derivation of words, f. pp. stem of *originare.”, where the Latin verb originare is mentioned.

As a result it could be that there were two latin verbs oriri and originare.

Although the gender of the suffix is not listed there, but we do have origo which is listed as a feminine noun in wiki (http://en.wiktionary.org/wiki/origo) with a plural of origines, thus the suffixes -igo and -igin could in fact be feminine suffixes.